RE: [ipfix] STCP as a default transport not
"Carter Bullard" <carter@qosient.com> Fri, 10 October 2003 15:49 UTC
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Reply-To: carter@qosient.com
From: Carter Bullard <carter@qosient.com>
To: "'MEYER,JEFFREY D (HP-Cupertino,ex1)'" <jeff.meyer2@hp.com>, 'Benoit Claise' <bclaise@cisco.com>
Cc: stbryant@cisco.com, alex.audu@alcatel.com, 'Reinaldo Penno' <rpenno@nortelnetworks.com>, ipfix-chairs@net.doit.wisc.edu, ipfix@net.doit.wisc.edu, rrs@cisco.com
Subject: RE: [ipfix] STCP as a default transport not
Date: Fri, 10 Oct 2003 11:35:52 -0400
Organization: QoSient, LLC
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My principal concern is that SCTP is too young to be the only transport. For example, a recent Univ. of Delaware Technical Document, co-authored by Cisco, identifies a serious problem with SCTP congestion control when there are multiple drops in a single window, causing it to degrade "more than necessary to be 'TCP-friendly', i.e. it grinds to a dribble for a little while, while transmitting more packets. The link where you can get the publication is: http://www.eecis.udel.edu/~amer/PEL/poc/index.html The paper is "SCTP and TCP Variants: Congestion Control Under Multiple Losses", very recent. The point is that these are the normal growing pains of a new protocol, but SCTP and PR-SCTP still have some problems to iron out. Like Jeff, I have no problems with IPFIX running over PR-SCTP, but not as the only protocol. Carter > -----Original Message----- > From: MEYER,JEFFREY D (HP-Cupertino,ex1) [mailto:jeff.meyer2@hp.com] > Sent: Friday, October 10, 2003 9:46 AM > To: 'Benoit Claise'; MEYER,JEFFREY D (HP-Cupertino,ex1) > Cc: stbryant@cisco.com; alex.audu@alcatel.com; > carter@qosient.com; 'Reinaldo Penno'; > ipfix-chairs@net.doit.wisc.edu; ipfix@net.doit.wisc.edu; rrs@cisco.com > Subject: RE: [ipfix] STCP as a default transport not > > > Benoit, > > I am not in any way against specifying IPFIX on top of PR-SCTP, > what I am against is making that the ONLY supported transport. > This is for practical reasons, like availability of implementation. > And as cited before because of transport protocols' affinity > for running in kernel vs. user space, the availability is going > to be a lot slower coming than one might like. > > I would liken this to deciding to define a transport layer > protocol which could only run on IPv6 and not IPv4. You could, > but if you can run on both, I think there are decided benefits. > > The Diameter authors seemed to have made this pragmatic choice. > > It is a bit ironic that previous decisions of the WG around > choice of candidate protocols were ultimately trumped by "practical > reasons" like NF is more widely deployed, despite the fact > that it was the only protocol with NO binding to a congestion > aware transport. And now, the arguments seem to be a complete > 180 change. > > Regards, > > Jeff Meyer > > > -----Original Message----- > > From: Benoit Claise [mailto:bclaise@cisco.com] > > Sent: Friday, October 10, 2003 3:26 AM > > To: MEYER,JEFFREY D (HP-Cupertino,ex1) > > Cc: stbryant@cisco.com; alex.audu@alcatel.com; carter@qosient.com; > > 'Reinaldo Penno'; ipfix-chairs@net.doit.wisc.edu; > > ipfix@net.doit.wisc.edu; rrs@cisco.com > > Subject: Re: [ipfix] STCP as a default transport not > > > > > > Jeff, > > > > My point is that I'm convinced that SCTP-PR gives all the > advantages > > in one transport protocol. See the recent postings from Peter > > Lei; he knows the protocol a lot > > better than I do! > > Having the full flexibility (reliable, unreliable, partially > > reliable) in one transport protocol would be a plus. > > Let's give the flexibility to the different implementations. > > On the top of that, we don't know yet the future applications > > of IPFIX: > > PSAMP is one, exporting SLA information?, some MIB variables > > export?, etc... everything is possible since IPFIX is a generic > > export format. > > As I said, I think we should just use the right protocol > > instead of just > > using what exists. IMHO, SCTP_PR should be the target as transport > > transport. So, I would vote for SCTP with the PR extension. > > > > Regards, Benoit. > > > > > > >Benoit, > > > > > > SCTP-PR does not make me happy, nor do the previous decisions > > >around reliability as it regards to billing. > > > > > > Dropping packets under congestion is already done by UDP, and > > >UDP is ubiquitous in all OS's. > > > > > > Is there some challenge in defining IPFIX over TCP? It seems > > >to me that this is the easier case, there are less things to map > > >to vs. SCTP-PR. Is explicitly NOT defining a mapping to TCP > > >your proposal, i.e. force the use of SCTP-PR? > > > > > > As with the experience of Diameter, specifying both transports > > >will enable a migration to SCTP-PR for everyone if it actually > > >proves to have the values espoused and it is readily available. > > >In the interim having a TCP mapping (and UDP) would address the > > >requirements which I've encountered (billing issues aside). > > > > > > As Peter pointed out the resource constraints on the exporter > > >imposed by TCP can be mitigated in the implementation. > > > > > >Regards, > > > > > > Jeff Meyer > > > > > > > > > > > >>-----Original Message----- > > >>From: Benoit Claise [mailto:bclaise@cisco.com] > > >>Sent: Thursday, October 09, 2003 9:15 AM > > >>To: stbryant@cisco.com > > >>Cc: alex.audu@alcatel.com; carter@qosient.com; 'Reinaldo Penno'; > > >>'MEYER,JEFFREY D (HP-Cupertino,ex1)'; > > ipfix-chairs@net.doit.wisc.edu; > > >>ipfix@net.doit.wisc.edu; rrs@cisco.com > > >>Subject: Re: [ipfix] STCP as a default transport not > > >> > > >> > > >>Dear all, > > >> > > >>There are advantages regarding the use of SCTP versus TCP > > (discussed > > >>already on the list) but I think that the biggest advantage > > >>of SCTP is > > >>actually the extension SCTP-PR. And I'm surprised to see no > > >>reactions on > > >>the email below. > > >>Yes, I know that the SCTP-PR is not a standard yet but I > > >>think that we > > >>should just take the right protocol instead of just using > > what exists > > >>because it exists! > > >> > > >>I remember the heated discussions maybe one year ago about > > >>using IPFIX > > >>for billing, about high availability, etc... > > >>And one of the solution that could make everybody happy > is: SCTP-PR. > > >>We know that we do have some memory issues with TCP on the > > >>high-end routers. > > >>But, for the smaller exporter OR if you can afford/if it's > > >>possible to > > >>pack the exporter with the appropriate amount of memory, > > >>SCTP-PR would > > >>work perfectly well! > > >>Now, in the majority of cases (no billing, no enough > > memory/too many > > >>flow records, etc...) SCTP-PR would drop the flow records > > >>excess if any, > > >>which I think is the right thing to do. > > >> > > >>Regards, Benoit. > > >> > > >> > > >> > > >> > > >>>I think that the interest is in using PR-SCTP as described in > > >>> > > > >>>http://www.ietf.org/internet-drafts/draft-ietf-tsvwg-prsctp-01.txt > > >>> > > >>>rather than RFC 2960 SCTP. > > >>> > > >>>This claims the following benefits: > > >>> > > >>> > > >>>1.3 Benefits of PR-SCTP > > >>> > > >>> Hereafter, we use the notation "PR-SCTP" to refer to the SCTP > > >>> protocol extended as defined in this document. > > >>> > > >>> The following are some of the advantages for integrating > > >>> > > >>> > > >>partially > > >> > > >> > > >>> reliable data service into SCTP, i.e., benefits of PR-SCTP: > > >>> > > >>> 1. Some application layer protocols may benefit from > > >>> > > >>> > > >>being able to > > >> > > >> > > >>> use a single SCTP association to carry both reliable > > >>> > > >>> > > >>content, -- > > >> > > >> > > >>> such as text pages, billing and accounting > > information, setup > > >>> signaling -- and unreliable content, e.g. state that > > >>> > > >>> > > >>is highly > > >> > > >> > > >>> sensitive to timeliness, where generating a new > > >>> > > >>> > > >>packet is more > > >> > > >> > > >>> advantageous than transmitting an old one [1]. > > >>> > > >>> 2. Partially reliable data traffic carried by PR-SCTP > > >>> > > >>> > > >>will enjoy the > > >> > > >> > > >>> same communication failure detection and protection > > >>> > > >>> > > >>capabilities > > >> > > >> > > >>> as the normal reliable SCTP data traffic does. This > > >>> > > >>> > > >>includes the > > >> > > >> > > >>> ability to: - quickly detect a failed destination > address; - > > >>> fail-over to an alternate destination address, and; > > >>> > > >>> > > >>- be notified > > >> > > >> > > >>> if the data receiver becomes unreachable. > > >>> > > >>> 3. In addition to providing unordered unreliable data > > >>> > > >>> > > >>transfer as > > >> > > >> > > >>> UDP does, PR-SCTP can provide ordered unreliable > > >>> > > >>> > > >>data transfer > > >> > > >> > > >>> service. > > >>> > > >>> 4. PR-SCTP employs the same congestion control and congestion > > >>> avoidance for all data traffic, whether reliable or > > partially > > >>> reliable - this is very desirable since SCTP enforces > > >>> TCP-friendliness (unlike UDP.) > > >>> > > >>> 5. Because of the chunk bundling function of SCTP, > reliable and > > >>> unreliable messages can be multiplexed over a > single PR-SCTP > > >>> association. Therefore, the number of IP datagrams > > >>> > > >>> > > >>(and hence > > >> > > >> > > >>> the network overhead) can be reduced versus having > > >>> > > >>> > > >>to send these > > >> > > >> > > >>> different types of data using separate protocols. > > >>> > > >>> > > >>Additionally, > > >> > > >> > > >>> this multiplexing allows for port savings versus > > >>> > > >>> > > >>using different > > >> > > >> > > >>> ports for reliable and unreliable connections. > > >>> > > >>>---------- > > >>> > > >>>PR-SCTP has the option of being able to configure the > > >>> > > >>> > > >>exporter to work > > >> > > >> > > >>>on a > > >>>best effort data export basis, rather than being > > >>> > > >>> > > >>constrained to work on a > > >> > > >> > > >>>reliable basis. > > >>> > > >>>We should spend some time thinking about the behaviour we > > >>> > > >>> > > >>want in the > > >> > > >> > > >>>exporter when the network is congested, perhaps due to an > > >>> > > >>> > > >>attack. PR-SCTP > > >> > > >> > > >>>gives us the option of running a best effort data > > >>> > > >>> > > >>collection to gleen > > >> > > >> > > >>>what > > >>>is going on, when a TCP based exporter would otherwise > > >>> > > >>> > > >>collapse due to > > >> > > >> > > >>>backlog on the exporter. > > >>> > > >>>Stewart > > >>> > > >>> > > >>> > > >>> > > >>>-- > > >>>Help mailto:majordomo@net.doit.wisc.edu and say "help" in > > >>>message body > > >>>Unsubscribe mailto:majordomo@net.doit.wisc.edu and say > > >>>"unsubscribe ipfix" in message body > > >>>Archive http://ipfix.doit.wisc.edu/archive/ > > >>> > > >>> > > >> > > >> > > >> > > > > > -- Help mailto:majordomo@net.doit.wisc.edu and say "help" in message body Unsubscribe mailto:majordomo@net.doit.wisc.edu and say "unsubscribe ipfix" in message body Archive http://ipfix.doit.wisc.edu/archive/
- [ipfix] STCP as a default transport not Carter Bullard
- Re: [ipfix] STCP as a default transport not Alex Audu
- RE: [ipfix] STCP as a default transport not Carter Bullard
- Re: [ipfix] STCP as a default transport not Alex Audu
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Reinaldo Penno
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Tal Givoly
- Re: [ipfix] STCP as a default transport not Alex Audu
- Re: [ipfix] STCP as a default transport not Stewart Bryant
- RE: [ipfix] STCP as a default transport not Reinaldo Penno
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Carter Bullard
- Re: [ipfix] STCP as a default transport not Alex Audu
- Re: [ipfix] STCP as a default transport not Stewart Bryant
- Re: [ipfix] STCP as a default transport not Stewart Bryant
- Re: [ipfix] STCP as a default transport not Stewart Bryant
- IPFIX meeting slot has been requested for the 58t… Dave Plonka
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Reinaldo Penno
- Re: [ipfix] STCP as a default transport not Benoit Claise
- Re: [ipfix] STCP as a default transport not Benoit Claise
- Re: [ipfix] STCP as a default transport not Peter Ludemann
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Randy Bush
- RE: [ipfix] STCP as a default transport not Brown, Mark R, ALABS
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Randy Bush
- RE: [ipfix] STCP as a default transport not Peter Lei
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Randy Bush
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Stas Khirman
- RE: [ipfix] Congestion management Nevil Brownlee
- RE: [ipfix] STCP as a default transport not Carter Bullard
- Re: [ipfix] STCP as a default transport not Benoit Claise
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] Congestion management Randy Bush
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- Re: [ipfix] STCP as a default transport not Randall Stewart (cisco)
- RE: [ipfix] STCP as a default transport not Carter Bullard
- RE: [ipfix] STCP as a default transport not Carter Bullard
- Re: [ipfix] STCP as a default transport not Peter Ludemann
- Re: [ipfix] Congestion management Stewart Bryant
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- Re: [ipfix] STCP as a default transport not Robert Lowe
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- Re: [ipfix] STCP as a default transport not Peter Lei
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- Re: [ipfix] STCP as a default transport not Alex Audu
- Re: [ipfix] STCP as a default transport not Peter Lei
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- RE: [ipfix] default transport !!! Nevil Brownlee
- Re: [ipfix] STCP as a default transport not Alex Audu
- RE: [ipfix] STCP as a default transport not MEYER,JEFFREY D (HP-Cupertino,ex1)
- Re: [ipfix] STCP as a default transport not Alex Audu
- RE: [ipfix] STCP as a default transport not Carter Bullard
- [ipfix] reporting about tossed data Maurizio Molina
- Re: [ipfix] default transport !!! Mark Fullmer
- Re: [ipfix] default transport !!! Randall Stewart (cisco)
- Re: [ipfix] default transport !!! Randy Bush
- Re: [ipfix] default transport !!! Mark Fullmer
- Re: [ipfix] default transport !!! Robert Lowe
- Re: [ipfix] default transport !!! Mark Fullmer
- Re: [ipfix] default transport !!! Randall Stewart (cisco)